Section 08 / Pins and keys

Dowel pins ground 0.0002 in over, for a real press fit.

Hardened dowel pins and keystock for fixtures, tooling and power transmission. Alloy pins at 58 HRC minimum in inch and metric, 1045 cold-drawn keystock by the foot, and slotted and coiled spring pins by the box. The fit is decided by your reamer, so the tolerance notes are on this page.

58 HRC min 1/8 to 1/2 in, 3 to 12 mm 1045 keystock

58HRC minimum, pins

+.0002Oversize, in

Hardened steel dowel pins standing in a ground steel block — Pins come in packs of 10 or 25, sealed in oil paper. Leave them wrapped until they go in the hole.

Line 08.1 / Hardened dowel pins

Hardened dowel pins

Through-hardened alloy steel, 58 HRC minimum surface, ground and polished, with a chamfer on one end and a radius on the other. They locate one plate to another in a fixture, a die set or a gearbox split line, so the bolts only clamp and the pins take the shear and the position.

Standard inch pins are made 0.0002 in over nominal. A 1/4 in pin measures about 0.2502 in, so it presses into a hole reamed at 0.2500 in and slips into a hole reamed 0.0005 to 0.001 in over. That is the whole trick of dowelling: one tight hole, one slip hole. Pressing a pin into two tight holes means you will never get the plates apart without a puller.

We do not sell soft or unhardened pins as dowels. They mushroom on the first press and they wear oval in a fixture that sees parts loaded a few thousand times.

Material: Alloy steel, through-hardened
Hardness: 58 HRC minimum
Inch: 1/8 to 1/2 in diameter, nominal +0.0002 in
Metric: 3 to 12 mm, m6 tolerance
Ends: One chamfered, one radiused
Price basis: Per pack of 10 or 25

Square keystock beside a keyed shaft and slotted spring pins — Keystock is cut on the same saw as bar. Ends deburred, length written on the piece.

Line 08.2 / Keystock and spring pins

Keystock and spring pins

Keystock is 1045 cold-drawn square bar sized to fit a standard shaft keyway, from 1/8 to 1 in square. Cold-drawn stock runs slightly oversize so you can file it to a tap fit in the keyway. Plain cold-rolled flat bar sold as keystock is usually undersize, and a key that rocks in its seat chews the keyway out within weeks.

Sold per 12 in length, or cut to the length you give us. If you send the shaft diameter we will tell you the standard key size in the reply: a 1-1/4 in shaft takes a 1/4 in key, a 2 in shaft a 1/2 in key.

Spring pins are on the same shelf. Slotted pins in carbon and stainless for general retention, coiled pins where the hole sees shock or the part needs to come apart and go back together. Spring pins go into a hole at nominal size, not reamed oversize. The pin does the gripping.

Keystock: 1045 cold-drawn, 1/8 to 1 in square
Key tolerance: Oversize, for fitting to the keyway
Spring pins: Slotted and coiled, carbon and stainless
Price basis: Per 12 in length; spring pins per box of 100

Fit tolerance notes for inch dowel pins

MOD 08 / Fits

Standard 0.0002 in oversize pins. Hole sizes are reamed sizes; check your reamer with a pin gauge.
Nominal	Pin diameter	Press fit hole	Slip fit hole	Pack
1/8 in	0.1252	0.1250	0.1255 to 0.1260	25
3/16 in	0.1877	0.1875	0.1880 to 0.1885	25
1/4 in	0.2502	0.2500	0.2505 to 0.2510	25
5/16 in	0.3127	0.3125	0.3130 to 0.3135	25
3/8 in	0.3752	0.3750	0.3755 to 0.3760	10
1/2 in	0.5002	0.5000	0.5005 to 0.5010	10

Fit 01

Ream, do not drill to size

A twist drill leaves a hole 0.002 in or more oversize and out of round. Drill under, then ream.

Fit 02

Two pins, one slotted hole

On long fixtures, make one of the slip holes a short slot along the line between pins. It absorbs pitch error without losing location.

Fit 03

Blind holes need a vent

A press-fit pin in a blind hole traps air and springs back out. Use a pull-out dowel with a tapped end, or drill a small vent.

Fit 04

Metric pins are m6

An m6 pin presses into an H7 hole with light interference. For a slip fit in metric, ream F7 or G7.

Before you send the inquiry

Toolmakers, maintenance shops rebuilding gearboxes and anyone building a fixture plate are who this shelf is for. Send the nominal size, length, inch or metric, and pack count. For keystock, the square size and either 12 in pieces or a cut length.

Not here: undersize keystock, taper pins, or ground shafting. If you need stepped or custom keys machined, that is a machine shop job. We will cut a key blank from bar stock to length, but we do not mill it.

ZAVTILOLOT 08-A

ItemDowel pin, hardened

Size1/4 × 1 in

Diameter0.2502 in

Hardness58 HRC min

Count25 pcs

Size, length, count.Answered in writing.

Dowel pins by the pack, keystock by the foot, spring pins by the box. Stock and lead time in the reply.

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